Coil winding arbor



ly ,1967 H. STANTON, JR 3,329,374

COIL WINDING ARBOR Filed D80. 50, 1965 2 Sheets-Sheet 1 2}; f INVENTOR.

July 4, 1967 H. STANTON, JR

COIL WINDING ARBOR 2 Sheets-Sheet 2 Filed Dec. 30, 1965 United States Patent 3,329,374 COIL WINDING ARBOR Howard Stanton, Jr., Ipswich, Mass, assignor to Sylvania Electric Products Inc., a corporation of Delaware Filed Dec. 30, 1965, Ser. No. 517,703 6 Claims. (Cl. 242118.4)

This invention relates to arbors for precision winding of wire coils for iron core inductors, and particularly to arbors affording greatly improved taping of the fiinished coils.

The majority of modern inductors such as transformers, ballasts and reactors, comprise an iron core with four or more legs forming a closed flux path around a space occupied by one side or leg of a coil which surrounds one of the legs. Usually the core comprises two jointed parts which are separated when a preformed coil is slipped over one of the legs, the core parts then being rejoined. Prior to assembly on the inductor core the coil is wound on an arbor core of substantially the same cross section as the inductor core leg which the coil is intended to fit.

During winding, the axial width of the coil is limited by flanges or walls at each end of the arbor, the walls being mounted on a rotating spindle and also serving .to support the core on the axis of the spindle. Prior to starting the winding one or more adhesive tapes are laid on the core parallel to the winding axis and inwardly of the space to be occupied by the legs of the coil. When the coil is finished and before removing the coil from the arbor the tapes are wrapped around the legs to hold the turns of wire in place. For this purpose openings are cut through the end walls to receive the ends of the tape so that they do not occupy any of the coil space between the end walls.

In precision winding, after each layer of one wire thickness is wound across the core at a given pitch the pitch reverses in the overlying layer and each turn of the overlying layer crosses over a turn of the inner layer and then seats precisely in the groove-like space between two underlying turns. At the starting leg of the coil, that is, the leg where the starting end of wire enters the coil, the turns tend to bulge axially of the coil when they cross over underlying turns. In prior arbors it was possible for the crossover turns to bulge into the tape opening and disrupt the precision of the Winding. Imprecisely wound coils are bulky and difiicult to fit on the core legs for which they are intended. Also they do not accept a uniform coating of insulation into which they are dipped. Consequently with prior arbors the coils are taped at legs other than the crossover leg. The crossover leg was therefore unsecured, and the starting and finishing ends of the coils were loosely held, and when the coil was subsequently dipped in an insulating fluid received a thinner coat of insulation than the body of the coil.

The object of the present invention is to provide an arbor which allows taping at the crossover leg of the coil without axial bulging of the crossover turns, and

of layers are wound and adequately insulated.

According to the invention an arbor for precision wind- 3,329,374 Patented July 4, 1967 comprises a first portion supported onthe spindle and a second portion detachably secured to said first portion and having a face opposing the other wall member, said wall portions forming therebetween an opening extending into the face of and through said one end wall member for receiving an adhesive tape extending through the other wall member and said volume, whereby the face of said second, detachable wall portion confines the coil during winding and after said coil is wound around said core and volume said second wall portion may be removed to permit said tape to be secured around one leg of the coil.

For the purpose of illustration a typical embodiment of the invention is shown in the accompanying drawings in which:

FIG. 1 is an exploded isometric view of a coil winding arborj FIG. 2 is a fragmentary cross-section of a coil on the arbor of FIG. 1;

FIG. 3 is a plan view of the arbor;

FIG. 4 is a section on line 44 of FIG. 3;

FIG. 5 is a plan vie-w of an arbor end wall, parts being omitted;

FIGS. 6 and 7 are plan views of the omitted parts;

FIG. 8 is an end elevation of the end wall parts being omitted;

FIGS. 9 and 10 are end elevations of the omitted parts; and

FIG. 11 is an isometric view of an assembled coil and core.

As shown in FIG. 1 an arbor according to the present invention comprises two end wall members 1 and 2 having opposed, parallel, plane faces 10 and 20 between which are a pair of core blocks 3 and 4. A spindle 6 having a threaded end 7 passes through openings 8 in the end walls and secures the core blocks 3 and 4 on pins 9 which engage the bores 11 in the core blocks. The end walls and core blocks are held together by a nut 12 screwed on the threaded end 7 of the spindle 6. The axis of the spindle, end walls and core blocks is coincident with the axis of a coil 13 shown in completed form.

As shown in FIG. 2 an inner layer of turns of insulated wire 14 are wound on the core blocks 3 and 4 starting with one end 16 of wire and proceeding axially across the width of the core blocks between the end walls 1 and 2. The width of the core blocks 3 and 4 is equal to a desired whole number of wire diameters plus one-half a diameter, so that the beginning turn 17 of the second layer of turns 18 is wedged between the last turn of the inner layer of turns and the end wall 1. The starting turn 17 of the second layer reverses the winding pitch, crosses over the last turn of the first layer and seats in the groove-like space between the last two turns of the inner layer and in lateral contact with an adjacent turn 18 of the second layer. The first turn 19 of the third layer lies directly over the starting turn 16 of the coil and crosses over that turn and drops in and lies in the groove-like space between the last turn and next to last turn of the second layer. It is this first turn of the third and successive odd-numbered layers which tend to bulge axially of the coil and disrupt precise winding. For obscure reasons the bulging problem is negligible at the opposite side of the coil when the second layer is started.

As successive layers of wire turns are wound on the core blocks 3 and 4 the coil 13 is formed with a crossover leg 21, adjacent side legs 22 and an opposite end leg 23. As can be seen in FIG. 1 the crossover leg 21 of the finished coil is somewhat thicker than the adjacent side legs 22 and end leg 23 because of the added thickness imparted by the crossing of the wires of successive layers over the wires of the inner layer.

As shown in the figures the end block 1 has two deep recesses 24 cut at opposite sides. The purpose of these recesses is to receive tapes 25, each of which is laid through a recess 24 between the core blocks 3 and 4 and through an opening 26 formed between the major part of end wall 2 and a second part 27. The second part 27 has a face 29 coplanar with the inner face 20 of wall 2 and opposed to and parallel with the inner face of end wall 1. The second wall part 27 is detachably secured to the wall member 2 by a pin 31 extending into a socket 22 in the end wall and a thumb screw 32 received in a threaded socket 33. Adjacent the detachable wall part 27 is a third wall part 36 similarly secured to the end wall member 2 by a pin 37 fitting in a socket 38 and a screw 39 entering a threaded socket 41 in the end wall.2. The third end wall part 36 has a face 42 extending to the plane of the faces 29 and respectively of the second end wall part 27 and the end wall 2. A laterally slanted face 43 is spaced parallel to a face 44 on end wall member 2 so as to leave a slot therebetween for receiving the starting end 16 of the coil wire.

Prior to starting the winding of a coil the second end wall part 27 is detached from end wall 2 by removing the thumb screw 32. A length of adhesive tape is then laid in the recess 24 of end wall 1 and thence between the core blocks 3 and 4 and under the end wall part 27 in the groove 26. A similar length of tape is laid in opposite slots 24 of the two end walls 1 and 2. The starting end of coil wire is then wrapped around a stud 46 and led through the slot between faces 43 and 44 where the slot opens in the inner face on end wall 2 adjacent the slot 26 through end wall part 27.

A first layer of coil turns is then wound around the core blocks 3 and 4 by rotating the arbor on the spindle and feeding the wire from a spool (not shown), guiding the wire either continuously or stepwise lengthwise of the arbor blocks 3 and 4.

Either an odd or even number of layers for the coil may be wound on the arbor. As shown in coil 13 of FIG. 1 an odd number of layers have been wound and the finishing end 48 of the core is on the opposite side of the coil from the starting coil wire end 16. This finishing wire end 48 is led out from the coil at one side of the upper recess 24 in end wall 1. The hand screw 32 is then removed, the end wall part 27 lifted away from the tape and the tape is wrapped around the crossover coil leg 21 over the starting end 16 of the coil and the other tape end which has been wrapped over the finishing wire end 48. Similarly the lower tape is wrapped around the lower leg 23 of the wire 13. The spindle screw 12 is then removed and the end walls 1 and 2 and core blocks 3 and 4 broken apart permitting removal of the finished coil.

The taped coil is then dipped in a fluid insulating compound such as epoxy resin and coated with the insulation. The thickness of the coating over the coil depends on the precise and intimate contact of the turns of the coil. The detached wire ends 16 and 48 accumulate less insulation because they are not bound tightly to the coil. However, according to the present invention the first and last turns of the coil are held in intimate contact with the other turns, and only the necessary lead-out ends 16 and 14 are spaced from the body of the coil. Because the present arbor permits the crossover end of the coil to be taped and because the starting and finishing wire ends 16 and 48 are led out at the crossover ends the reduced thickness of insulation on the free ends does not present as great a danger of insulation failure as do the turns directly adjacent the core 52.

As shown in FIG. 11 the finished coil can then be slipped over one leg 51 of a known iron core 52 having two parts 53 and 54 comprised of interleaved and overlapping laminations 56.

A coil wound and taped on the present arbor has the advantage that the crossover end 21, having been confined by the face 29 of end wall part 27, is held with its turns in the precise relation shown in FIG. 2 during winding and, thereafter, by the tape 25. The starting and finishing ends 16 and 48 of wire are held by the tape in precise relation to the body of the coil 13 up to the point, outside the core 52, where they must be led away from the coil.

It should be understood that the present disclosure is for the purpose of illustration only and that this invention includes all modifications and equivalents which fall within the scope of the appended claims.

I claim:

1. An arbor for precision winding of a coil having connected legs formed by superimposed layers of wire turns, the turns of a superimposed layer being opposite in pitch to that of an adjacent layer and crossing over the turns of an inner layer at one side of the coil, said arbor comprising a spindle, two Wall members having opposed faces spaced axially on the spindle for confining the coil there between, and a core supported between said members, the core having peripheral surfaces defining a volume about which the coils are wound;

characterized in that at least one said wall member comprises a first portion supported on the spindle and a second portion detachably secured to said first portion and having a face opposing the other wall member, said wall portions forming therebetween an opening extending into the face of and through said one end wall member for receiving an adhesive tape extending through the other wall member and said volume, whereby the face of said second, detachable wall portion confines the coil during winding and after said coil is wound around said core and volume said second wall portion may be removed to permit said tape to be secured around one leg of the coil.

2. An arbor according to claim 1 wherein said one Wall member has a slot extending through said wall member outside said volume for receiving the end of the wire leading to the inner layer of wire turns, said slot being adjacent said second, detachable wall member portion.

3. An arbor according to claim 2 wherein said slot is formed by said first wall member portion and a third wall member portion extending to the face of said one wall member adjacent said tape opening for resisting the pressure of said coil against said second, detachable wall member portion.

4. An arbor according to claim 2 wherein said slot extends to the face of said one wall member adjacent said opening.

5. An arbor according to claim 1 wherein said opening has a cross section to grip said tape between said first and second wall member portions.

'6. An arbor according to claim 1 wherein said wall members are spaced apart a distance equal to the width of a whole number of wire diameters plus the width of one-half a wire diameter, whereby the layers of a coil started adjacent said detachable wall member portion cross over each other only adjacent said detachable portion, the face of the detachable portions confining the turns axially of the coil.

References Cited UNITED STATES PATENTS 2,400,008 5/1946 Korte 29 155.57 2,878,855 3/1959 Gakle et a1 29 155.57 X 3,149,297 9/1964 Rechel 336-209 LEONARD D. CHRISTIAN, Primary Examiner. 

1. AN ARBOR FOR PRECISION WINDING OF A COIL HAVING CONNECTED LEGS FORMED BY SUPERIMPOSED LAYERS OF WIRE TURNS, THE TURNS OF A SUPERIMPOSED LAYER BEING OPPOSITE IN PITCH TO THAT OF AN ADJACENT LAYER AND CROSSING OVER THE TURNS OF AND INNER LAYER AT ONE SIDE OF THE COIL, SAID ARBOR COMPRISING A SPINDLE, TWO WALL MEMBERS HAVING OPPOSED FACES SPACED AXIALLY ON THE SPINDLE FOR CONFINING THE COIL THEREBETWEEN, AND A CORE SUPPORTED BETWEEN SAID MEMBERS, THE CORE HAVING PERIPHERAL SURFACES DEFINING A VOLUME ABOUT WHICH THE COILS ARE WOUND; CHARACTERIZED IN THAT AT LEAST ONE SAID WALL MEMBER COMPRISES A FIRST PORTION SUPPORTED ON THE SPINDLE AND A SECOND PORTION DETACHABLY SECURED TO SAID FIRST PORTION AND HAVING A FACE OPPOSING THE OTHER WALL MEMBER, SAID WALL PORTION FORMING THEREBETWEEN AN OPENING EXTENDING INTO THE FACE OF AND THROUGH SAID ONE END WALL MEMBER FOR RECEIVING AN ADHESIVE TAPE EXTENDING THROUGH THE OTHER WALL MEMBER AND SAID VOLUME, WHEREBY THE FACE OF SAID SECOND, DETACHABLE WALL PORTION CONFINES THE COIL DURING WINDING AND AFTER SAID COIL IS WOUND AROUND SAID CORE AND VOLUME SAID SECOND WALL PORTION MAY BE REMOVED TO PERMIT SAID TAPE TO BE SECURED AROUND ONE LEG OF THE COIL. 